I had to stop using crashplan because there is no way to roll back revisions within a file. If a file gets corrupted it'll just back up the corrupted version on top of what was previously a good backup.
CrashPlan has versioning that is set (by default) to back up changed files in 15 minute increments. If a file is corrupted, CrashPlan will attempt to back up the changes as it is not a corruption detection utility.
However, it's versioning allows for a user to easily restore the uncorrupted file by selecting a date prior to the corruption occurring.
This process is explained in greater detail here:
https://support.code42.com/CrashPlan/4/Troubleshooting/Recov...
The default versioning can be adjusted, so ultimately it's the responsibility of the individual user to confirm the health of their backup and verify the versioning frequency that best fits their needs.